Circuit breaker



May 16, 1950 A. GUILLAUME ET AL. 2,507,971

CIRCUIT BREAKER Filed June 10, 1946 Patented May 16, 1950 CIRCUITBREAKER Andr Guillaume and Albert Thibaudat, Seine,

France, assignors to Forges et Ateliers de Constructions Electriques deJeumont, Paris,

France Application June 10, 1946, Serial No. 675,554 In France June 25,1945 12 Claims.

The operating conditions of modern electrical networks impose uponcircuit breakers, and particularly upon circuit breakers of the quickreclosing type, constantly increasing requirements with res-peet tobreaking capacity and speed. Moreover, in some high power circuitbreakers, it is dangerous to effect a very rapid reclosing of thecircuit followed by a new circuit break, in view of the fact that suchbreak runs the risk of being produced in an insufficiently regeneratedmedium. This drawback is particularly pronounced, for instance, incertain apparatus with a rectilinear movement of the contact rod whichis displaced in one and the same confined space. This at times makes itnecessary to provide for the re-closing of separate parts whichcomplicates the arrangement of the apparatus and increases their bulkand the price.

This invention, which applies to circuit breakers comprising two or morecut-outs in series, relates to means making it possible to bring aboutan appreciable increase in the circuit breaking speed and capacity, aswell as to avoid the drawback pointed out above.

In accordance with the present invention these favorable results can beobtained by improved means such as suitable guidance of the arcsresulting from a properly directed iluid ilow, proper selection of thespeed of the movable contacts, and by the application of resilient meansfor suitably delaying and prolonging the arc extinguishing action.

When a powerful circuit breaker interrupts a very high overload, theelectrodynamic forces and the whirling movements of the quenching fluidsare capable of elongating the arcs while giving them an irregular shape.This uselessly increases the thermic effects, imposes excessive forceson the circuit breaker and creates very substantial counter pressureswhich affect the circulation of the arc extinguishing iiuids. Moreover,by moving away from the trajectories of the movable contacts, the arcsmay more or less completely escape the blow-out action of these iluids,of which they ionize and heat parts which normally should remain freshin order to be available for a subsequent re-closing cycle.

In accordance with one aspect of this invention, all kthese drawbacksare avoided with the aid of suitable guiding parts arranged in thevicinity of the normal trajectory of the arcs subject ed to the actionof the quenching fluid, these parts being operated in such a way as tokeep said arcs on the trajectory of the movable contacts by the actionof the arc extinguishing fluid directed under the optimal conditions.

On the accompanying sheet of drawing,

Fig. 1 is a somewhat diagrammatic vertical section taken along line B-Dof Fig. 2, through an illustrative embodiment of the invention, asapplied to a rotating circuit breaker with a plurality vofmake-and-break points in a quenching fluid such as oil, and

Fig. 2 is a horizontal section along of Fig. 1.

On the said figures of drawing, the movable equipment is made up of arotatable insulating shaft I carrying an inclined rod 2 of conductivematerial, the said rod extending through a bore in shaft I, as shown.Except for the ends thereof, the exposed portions of rod 2 are sheathedin insulating material 2a. The free ends cooperate severally with thedouble-sided xed contacts 3 and 4. These contacts are of the samedouble-U type, the several U-shaped sockets, which snugly receive theaforesaid free ends of rod 2, being arranged to open in oppositedirections as shown. The contacts 3 and 4 are severally connected withlead wires 5 and 6. The parts are housed in cylindrical insulatingreceptacle 'I which is filled with oil or other suitable quenching iiuidup to level 8. The inset ends Ia and 'Ib of receptacle 'I are also ofinsulating material.

The parts can be arranged so that the lower arc, formed between thecontacts 2 and 4, is started a little sooner than the upper arc, formedbetween the contacts 2 and 3, so that the upline E-F per arc is at asuitable moment subjected to the extinguishing action engendered by thelower arc.

The upper end of contact rod 2 moves in the annular channel 9, Fig. 1,provided in a diskshaped part I2 of insulating material mountedinteriorly of end Ia and in juxtaposition thereto. A similar annularchannel can be provided in the lower part of the receptacle 'I on theupper face of the inset 1b. Communication between the oil well formedabove end 'Ia and the interior of receptacle 'I is realized through themedium of aligned bores I0 and I3 provided respectively in parts I2 and1a. An arc extinguishing exhaust flow of oil is thus directed to pushthe upper arc towards the bottom of the channel 9, notwithstanding theshown open form and the relative shallowness of the latter. By suitablyconfiguring channel 9-as for instance arranging the inner wall thereofobliquely as illustratedand by disposing openings I0 and I3 at thepoints where the arc rupture always occurs, the oil is directed underthe most favorable conditions and maximum arc extinguishing effect isrealized.

It will be clear that, regardless of the type of circuit breaker, theare is thus effectively kept on the trajectory of its movable electrode,which makes it possible to impart an optimal length thereto. Thesuccessive breaks, which are connected in series, can be staggered insuch manner as to cause the blow out action to take place at the mostfavorable instants. Finally, in order that the breaks may be mostenicacious from the standpoint of time, the speed of the movablecontacts may be suitably selected and varied as a function of the shapeand construction of the guiding parts.

It has been found that by the combined expedients of staggering thepoints of disconnection, the guiding of the arcs, the directed quenchingend the suitable speed of the movable contacts, a very appreciableincrease in the power and speed of interruption is realized.Furthermore, owing to the immobillty of the quenched arcs and to thedirected fluid flow, the hot and ionized residue left by the blown arcsis Very quickly removed without its being able to ad-mix with thesurrounding fluid. This accelerated regeneration of the dielectricstrength constitutes an important advantage, particularly as regards therapid re-closing of the circuit breakers.

In the illustrated embodiment, this advantage is of especialsignificance. In the course of its first circuit interruption, the upperend of the contact rod 2 describes the arc of circle AB shown in Fig. 2;in the course of the :re-closure it describes the arc BC and during thesecond circuit interruption the arc CB. Each of the angles AB and BC canbe practically equal to 180.

It ls therefore seen that the successive cycles of the reclosingoperation utilize different semicircles of the guiding channel 9, and inview of the fact that each time the residue from the arc is preventedfrom contaminating the oil of the other half of the trajectory, there-closing and the entire second cycle are always effected in a freshenvironment, that is to say under very good conditions. Thus theappreciable result is that in the course of the second break thedisconnecting power of the circuit breaker is the same as in the courseof the first, which represents an important advantage as against certain`apparatus wherein the second interruption does not have the same power.

The operation described can be improved by providing on the shaft l arotating obturator I!! which, of the openings l and I3, only unmasksthose which are in the vicinity of the arc.

It goes without saying that the means of this invention and theirvariations can be applied not only to rotating oil jet circuit breakerswhich have just been mentioned by way of example, but to other circuitbreakers having two or more breaking points in series and comprising aliquid or gaseous quenching.

When the arc extinguishing fluid is a liquid, it may be ladvantageous toattenuate the hydraulic excess pressure and more particularly to prolongits action by the application of suitable elastic parts adapted tomodify the moment of initiation as well as the intensity and duration ofthe arc extinguishing fluid ow. This makes it possible to have greaterfreedom in the choice of the speed of the contacts, of the displacementsamong the series breaks, of the shape and section of the guidingchannels, of their circulation openings, etc.

In the particular case of the device described above it is possible touse with that end in View for instance a toroidal body Il, Fig. 1, madeof elastic material such as rubber and lled with air, as well as anyother elastic means capable of producing the above effects. Thesedevices can be placed in the suitable parts of the circuit breakers, forinstance near the first partial arc.

We claim:

l. In a circuit breaker of the fluid blast type having a housing withtwo end walls, arc-blowing exhaust openings in the upper end wall and aplurality of fixed and movable contacts producing at least two arcs inseries, means guiding the exhaust llow of said fluid from said housingthrough said openings comprising a relatively shallow groove-likechannel in the underside of the upper end wall, opening towards theinterior of said housing, said channel partially surrounding the path ofa movable contact and said exhaust openings being located in saidchannel whereby an arc formed may be maintained freely in Said channelby the action of the fluid blast in lixed position along the path ofsaid movable contact and in front of said arc-blowing exhaust openings.

2. In a circuit breaker of the fluid blast type according to claim I,wherein a pressure responsive elastic means positioned within the saidhousing is provided to cooperate with said guiding means for delayingand lengthening the action of the guided fluid blast.

3. A circuit breaker of the character described: comprising a housingwith two end walls containing an arc-extinguishing fluid and having aplurality of arc-blowing exhaust openings in the upper end wall forcarrying a flow of said fluid, a pair of spaced fixed terminal contacts,a movable contact element engageable after a practically completerotation with said fixed contacts, whereby the medium in which thecircuit interruption and incident arc formation take place is alwaysdifferent from the medium in which the preceeding and succeeding circuitinterruptions and arc formations take place, 4and means for guiding theexhaust flow from said housing towards said openings to maintain by saidexhaust flow a non-confined arc along the path of its movable contact infront of said openings, said flow guiding means being formed by arelatively shallow groove-like circular channel located in the undersideof the upper end wall7 opening towards the interior of said housing andpartially surrounding the path of an end of said movable contactelement, and said exhaust openings being located in said channel.

4. A circuit breaker of the character described; comprising a housingwith two end walls containing an insulating arc-extinguishing fluid andhaving in the upper end wall a plurality of exhaust arc-blowing openingsfor said fluid, a pair of spaced fixed terminal contacts, a movablecontact element engageable with said fixed contacts, means guiding theflow of said fluid from said housing to said blowing openings forproducing an efficient arc extinction in said openings, said last namedmeans comprising a relatively shallow groove-like channel located in theunderside of the upper end wall, opening towards the interior of saidhousing and having at its bottom said exhaust openings whereby an arcformed is immobilized by the action of the fluid flow along the path ofthe movable contact in front of said openings so that said arc isefficiently extinguished although non-coniined.

5. A circuit breaker of the character described, comprising a housingwith two end walls containing a dielectric arc extinguishing fluid andhaving a plurality of arc blowing exhaust openings to discharge saiduid, a pair of spaced iixed terminal contacts, a movable contact elementmounted to effect a full rotation and to cooperate with said fixedcontacts whereby the space in which the arc is formed during aninterruption is always different from the space in which the succeedingarc is formed, elastic pressure responsive elements positioned withinthe said housing to increase the duration of said arc blowing dischargeflow and means for directing said discharge flow from said housingthrough said arc blowing openings and for maintaining freely lan arcformed in the path of its movable contact in front of said openings bythe action of said directed flow, said last named means comprising anopen and relatively shallow groove like channel in the underside of theupper end wall, partially surrounding the path of an end of the movablecontact element and opening towards the interior of said housing,whereby the arcs although non-restrained are immobilized in optimumposition.

6. A circuit breaker of the character described; comprising a housingwith two end walls containing a dielectric fluid and having a pluralityof are blowing iiuid exhaust openings, a pair of spaced xed terminalcontacts, a movable contact element rotating at a predetermined rate ofspeed and effecting a full rotation to engage with said iixed contactswhereby the space and the medium in which an arc is formed is alwaysdiiTerent from the space and the medium in which a succeeding arc isformed, and guiding means for directing said i'luid from said housing tosaid iarc blowing exhaust openings to maintain freely an arc in optimumposition in the path of the movable contact in front of said openings bythe action of the uid flow to produce an eilicient arc extinction, saidlast named means comprising an inwardly open relatively shallowkcircular channel iri the underside of the upper end wall, having theform of a recess with obliquely disposed walls partially surrounding thepath of said movable contact mem-ber `and said openings being located atthe bottom of said recess.

, 7. A circuit breaker of the character described; comprising asubstantially cylindrical housing having two end walls, the upper endwall being inset to provide a well thereabove, said housing and saidwell containing ia dielectric fluid, resilient pressure responsivemeans, said upper end wall having a plurality of arc blowing exhaustopenings therein providing communication between said housing and well,a pair of spaced iixed double sided contacts mounted on said end walls,and a rotatable contact member having ends engageable successively withboth sides of said iixed contacts, said upper wall having at itsinterior surface an inwardly open relatively shallow annular iluidguiding recess havingsaid exhaust openings located at the bottomthereof, the upper fixed contact oi' said fixed contacts being disposedin said recess and the path of movement of the upper end of saidrotatable contact member being located in said recess, said fluidguiding recess maintaining freely the upper arc formed by dynamic actionof the exhaust flow in the path of said rotatable contact in iront ofsaid exhaust openings, said dynamic action being lengthened by theaction of said resilient pressure responsive means, positioned insidesaid housing.

8. A circuit breaker according to claim '1, wherein the inner walls ofsaid recess are obliquely disposed to guide the arc extinguishing iiuidin optimal manner from the housing to the exhaust openings in order toimmobilize the upper arc in optimum position with respect to the fluidflow.

9. A circuit breaker according to claim 7, wherein the inner walls ofsaid recess are obliquely arranged to direct the dielectric fluid inoptimal manner for fixing freely the upper arc in non-confined positionwhereby the lprolonged blow-out action is most eiiicient, and arotatable shaft extending through said housing and having said movablecontact member airlxed thereto.

10. In a circuit breaker, an interrupting unit comprising an insulatinghousing with two end walls containing dielectric arc extinguishing fluidand having a, plurality of are extinguishing fluid discharge openings inthe upper end wall thereof, two fixed contacts, a rotatable contactmember engageable with saidrlxed contacts, fluid guiding meanscomprising in the underside of the upper 'end wall an inwardly openrelatively shallow annular recess having said discharge openings thereinand wherein one of said xed contacts is mounted, the path of movement ofone end of said rotatable contact member also being located in saidrecess, said recess maintaining by the dynamic action of said fluiddischarge iiowing from said housing to said openings the non-coniinedupper arc in the said path oi the contact member in front of saidopenings and directing said iiuid in optimal manner, and a pressureresponsive elastic element located inside of said housing andcooperating with said fluid guiding means for delaying and lengtheningthe action of said fluid discharge.

11. A circuit breaker according to claim 10, wherein the elastic elementdisposed intermediate the ends ofthe housing is an air lled member.

12. A circuit breaker according to claim 10, wherein means are providedfor selectively obturatin-g said exhaust openings.

ANDR GUILLAUME. ALBERT THIBAUDAT.

REFERENCES CITED Ihe following references are of record in the file ofthis patent:

STATES PATENTS Number Name Date 438,118 Smith Oct. '7, 1890 1,537,352Hilliard May 12, 1925 1,566,091 Hilliard Dec. 15, 1925 1,899,605 BakerFeb. 28, 1933 2,051,196 Barfoed Aug. 18, 1936 2,100,753 Schofield et alNov. 30, 1937 2,239,243 Moncharnps Apr. 22, 1941 FOREIGN PATENTS NumberCountry Date f 833,188 France July 18, 1938 852,550 France Oct. 30, 1939

